Remember this summer? From mid-May thru August the lag was even worse, usually worse lag spikes. The lag got better for a few days in early August just after the latest maphack banning. So why now again? Because it's holiday season in the United States. Students are just finishing up finals. Starting Nov. 24th was the Thanksgiving holiday and it won't end until after New Years Day, 3 major holidays.
As game maker you will often get 'fail to join' which really means failed to make, and probably will receive a 5 min penalty for whatever idiotic reason. Or you will try to enter a not full game, and get 'game full', which lasts about 2-3 minutes. During this time, the game won't appear on the game list and no one can join. Here, clearly Blizzard's computers can't count. Or you may go from one char to another too quickly, or make too many games too rapidly and receive a 'realm down' or 'cannot connect' msg, and that is a 5-10 min penalty. Or you may exit a game and very rapidly create or join the next or another game, and you get a 'failed to join' msg and you are hung up with the door not opening to the game and the silly msg, for about 45 seconds to a minute.
-The very rapid make/join penalty is an anti-duping penalty thats been around since 2003. The idea was to drop something on ground, exit during some sort of lag, and return with another character before the servers could catch up. It's annoying, but counting 5 seconds before rejoining or making seems to be best.
-Switching from one char to another, several times and rapidly, even if u DON'T join a game, causes your account to be flagged and if you exit from the character menu (the screen where u have selected a character and have the options of joining chat or seeing game list) too quickly, you will get a realm down type of penalty. This is very annoying when you do 2 sorts of things: going thru your mules looking for a certain item, and logging into your chars to refresh the expiration countdown.
-The inexplicable ability to make or join for a full 5 minutes often happens if you exit a laggy game during a lag spike. You're a duper! ....or so Blizzard's brainless computers ascertain. It also happens every few games anymore, especially if you are in a series of games, be they mf or exp games. Whether it's certain you are going to be penalized even before u hit the 'Enter' or 'Create' button hasn't been established. Maybe you try to join on a server that is undergoing some lag and get socked with the penalty. The next guy will have been with you the previous few games and will join just a few seconds later and get in, without penalty.
Now back to the seasonal lag issue. Why is it that an extra 20-30% players cause so much lag? Are Blizzard's servers dedicated to Diablo2 so old or so few anymore? Or perhaps when these guys get out of school they want their 'instant godliness' and do bots. Back when 75,000 people played this game at a time, it would be quite laggy from 8-10 pm every night, and from mid afternoon to evening on weekends. Nowadays, even with only 25,000 ppl on, the lag can occur anytime. Is that because the bots are running 24/7 with only one person games? Are their duping bots out there with the ability to lag the game or the entire server? Or perhaps Blizzard is causing artificial lag to crash the bots. Have you ever been in an LoD game where the Baal-bot stands motionless for a few seconds and then exits, its programming warning it to go? A well-worded question can often provide half the answer.....sheer speculation on my part.